The Draganflyer X6 drone is among those approved for use by such organizations as law enforcement and the U.S. Customs and Border Protection agency. / Handout

by Judy Keen, USA TODAY

by Judy Keen, USA TODAY

Congress and at least 10 state legislatures could consider bills this year that would limit the use of the camera-equipped, unmanned aircraft in the USA.

As of last week, 348 drones were approved for domestic use, the Federal Aviation Administration says. More than half the applications submitted through August 2012 were from the Defense Department; law enforcement filed 7% and academic institutions 24%. Universities are researching their use in disaster response, agriculture and other areas.

Growing public wariness about the loss of privacy is driving concerns about drones, says Joanne Gabrynowicz, director of the National Center for Remote Sensing, Air and Space Law at the University of Mississippi. "I think concerns are going to mount," she says.

Drones are "fine for killing terrorists ... but I don't think they should be used to spy on American citizens," says Florida state Sen. Joe Negron, a Republican who introduced a bill last month to prohibit their use by law enforcement except to prevent terrorism.

Among other legislative efforts:

Last month, state Sen. Alex Padilla, a Democrat, introduced a bill that would regulate drones in California. He worries they'll be used to "infringe upon fundamental constitutional rights."

Rep. Ed Markey, D-Mass., introduced a bill in December that would establish national privacy safeguards and limit surveillance.

A bill introduced in Missouri by Rep. Casey Guernsey, a Republican, would require warrants before drones gather evidence. "I don't like the idea of Missouri becoming a police state," he says.

Gary Brunk of the American Civil Liberties Union of Kansas and Western Missouri, says drones "are going to become a feature of American life, unfortunately."

The Mesa County, Colo., Sheriff's Office has two drones that are "just another tool in our toolbox," spokeswoman Heather Benjamin says.